XBMC as DLNA/UPnP Digital Media renderer (DMR)

XBMC can be easily configured as DLNA/UPnP  Digital Media renderer (DMR).

Digital Media Renderer (DMR): These devices play content received from a digital media controller (DMC), which will find content from a digital media server (DMS).

Examples :
DMR : PC / laptop with XBMC running
DMC : Your smart phone - Android and iphone has many applications so it can be used as DMC
DMS : NAS or PC/Laptop with DLNA server running. There are many free DLNA servers are available like serviio, PS3 media server, Twonly, etc

http://www.youtube.com/watch?v=Q3Fl1JO3Elg

Configuration: 
Start XBMC --> Settings --> Network --> Allow Control of XBMC via UPnP
That's it - you're done. Open DMC app on your smart phone and enjoy....